1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member, a method of producing the electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus.
2. Description of the Related Art
In recent years, for the purpose of extending the life of an electrophotographic photosensitive member, improving image quality, and increasing the processing speed of an electrophotographic apparatus, it has been desired to improve the mechanical durability (abrasion resistance) of an organic electrophotographic photosensitive member containing an organic photoconductive substance (charge generating substance) (hereinafter referred to as an “electrophotographic photosensitive member”). In order to improve the mechanical durability, in accordance with one technique, a surface layer of an electrophotographic photosensitive member contains a polymer produced by the polymerization of a compound having a polymerizable functional group.
Japanese Patent Laid-Open No. 2000-066425 discloses a technique for providing a surface layer with a polymer produced by the polymerization of a charge transporting substance having two or more chain-polymerizable functional groups to improve the abrasion resistance and the electric potential stability of an electrophotographic photosensitive member. Japanese Patent Laid-Open No. 2010-156835 discloses a technique for providing a surface layer with a charge transporting substance having two or more methacryloyloxy groups and a polymer of a composition containing no polymerization initiator to improve the polymerization reactivity of the charge transporting substance.
However, the present inventors found that, among the chain-polymerizable charge transporting substances described in Japanese Patent Laid-Open No. 2000-066425, a charge transporting substance having a methacryloyloxy group more improves polymerization efficiency and mechanical durability than a charge transporting substance having an acryloyloxy group, but needs to be improved with respect to image defects, such as black spots, and potential variation (variation in light area potential). The present inventors found that the technique described in Japanese Patent Laid-Open No. 2010-156835 tends to cause distortion of a charge transporting substance, resulting in insufficient prevention of image defects, such as black spots, and potential variation.